Tektronix 475 User Manual

Maintenance—475
5. Remove the shafts from the vertical POSITION
potentiometers on the Vertical Preamp circuit board.
Loosen the front setscrew in the couplers and pull the
shafts out through the front panel.
6. Remove the attenuator shields.
7. Unsolder the two resistors that connect the Vertical
Preamp circuit board to the Attenuator circuit boards.
8. Unsolder the two discaps that connect between the
Vertical Preamp circuit board and the Interface circuit
board.
9. Remove the actuator shaft from the 20 MHz
BW/TRIG VIEW switch. Loosen the setscrew and remove
the shaft through the front panel.
10. Remove the six securing screws from the Vertical
Preamp circuit board and remove the board from the
instrument.
To reinstall the Vertical Preamp circuit board, reverse
the order of the removal steps.
Vertical Mode Switch Circuit Board Removal
1. Remove the Vertical Preamp circuit board as outlined
previously.
2. Remove the two UNCAL light lenses. Pry them away
from the front panel with a fingernail and pull them
straight out.
3. Remove the knobs from both VAR controls and both
VOLTS/DIV switches.
4. Remove the knobs from the Input Coupling switches.
They can be removed by pulling them off by hand.
5. Unplug the ribbon cables from the Vertical Mode
Switch circuit board that run to the VOLTS/DIV sensi
tivity lights.
6. Unplug all remaining connectors from the Vertical
Mode Switch circuit board. Note wire color codes to
facilitate correct reinstallation.
7. Remove the two securing screws from the rear of the
Vertical Mode Switch circuit board.
8. Remove the four nuts that secure the attenuator
assemblies to the front casting.
9. Remove the Vertical Mode Switch circuit board from
the instrument.
To reinstall the Vertical Mode Switch circuit board,
reverse the order of the removal steps. To align the VERT
MODE switch pushbuttons, hold the assembly in place with
a slight forward pressure and use a small tool to reach
through the front panel to align the buttons. Install the
remaining parts in the reverse order they were removed. Do
not tighten the circuit board securing screws until the
securing nuts at the front of the attenuator chassis are tight
and the circuit board is aligned properly.
Trigger Generator And Sweep Logic Circuit Board
Removal
1. Remove the LOW LINE, TRIG, and READY light
lenses. Pry them away from the front panel with a
fingernail and pull them straight out.
2. Disconnect the six coaxial cables, single wire, and
two four-wire ribbon cables from the front of the Trigger
Generator And Sweep Logic circuit board. Note wire color
codes to facilitate correct reinstallation.
3. Disconnect the two coaxial cables and a five-wire
ribbon cable from the back side of the Trigger Generator
And Sweep Logic circuit board. Note wire color codes to
facilitate correct reinstallation.
4. Remove the actuator shaft from the POWER switch
coupler. Use a small flat-bladed screwdriver and exercise
caution so as not to damage the switch coupler.
5. Remove the POWER switch mounting bracket from
the Trigger Generator And Sweep Logic circuit board.
6. Unsolder the resistors from the External Trigger
Input connectors.
7. Remove the five board securing screws and remove
the circuit board from the instrument.
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Tektronix 475 Specifications

General

Brand	Tektronix
Model	475
Category	Test Equipment
Language	English